The end of the notice also means the Tierra Verde residents who had been required to boil water can return to normal water use.

Fort De Soto was closed early Saturday after customers and an alarm system revealed a water line break lowered pressure to a level that could allow harmful bacteria into pipes.

Officials still haven't determined what caused the breach, which prompted the boil water advisory for residential Tierra Verde south of Madonna Boulevard. Officials warned that drinking the water could cause diarrhea, cramps, nausea and headaches and was particularly dangerous to the very young and very old.

County spokeswoman Mary Burrell said the closure was specifically related to concerns about the park's water supply. The beach and surrounding waters were not contaminated.

Despite concerns, the first test of the water supply by the county's Department of Environment and Infrastructure didn't indicate contamination, Burrell said.

A second test Monday night showed the water was safe and the advisory was ended about 9 p.m.

Burrell said she estimated about 13,000 people were turned away from Fort De Soto this weekend.

Fort De Soto's 216 campsites were all occupied Saturday, and campers were not asked to leave, Burrell said. Rangers provided bottled water for drinking and cooking.

In addition to shuttering the park, the boil water advisory affected about 1,000 customers who live along the Pinellas Bayway in southern Tierra Verde.